class Point:
    def __init__(self, x, y):
        self.x = x
        self.y = y

    # 所以，在类中定义一个该方法，实例就可以像函数一样调用
    def __call__(self, *args, **kwargs):
        return 'Point is {}.{}'.format(self.x, self.y)


a = Point(4, 5)
print(a())
